Governing and regulating apparatus



Oct. 23, 1934, N. ARTsAY GOVERNING AND REGULATING APPARATUS 5Sheets-Sheet 2 Filed June 17. 1932 JAVA [7V IPOM PHI/F MOVE 16.

EOTAT/A/G REV:

V CAM V a s m n r N 5 .T. [@WA d I my N m 7 0 .3 8 a KIM m. m m Il W o h0 Q 8 2 M .0 2 .0 m. V m w m E Oct 23, 1934. R Y 1,977,980

GOVERNING AND REGULATING APPARATUS;-

File d June 17, 1932 3 Sheets-Sheet 3 138 VIII/ABLE. PRESJ'UKE TO SOU 82ROTATING CAM 62b REVERE/8L a acne/t E5 ELECTRIC 1 I INVENTQQ. N icho Ias A7 A TTORNEYS.

Patented Oct. 23, 1934 UNITED STATES PATENT OFFICE 20 Claims.

My invention relates to control apparatus adapted to govern the speed ofhydraulic or steam turbines or to control any other characteristic ofapparatus to maintain it constant within close limits.

The speed control of certain types of apparatus, of which hydraulicturbines may be considered as an example, has been a diilicult problem,but the art has finally adopted almost exclusively for such purposes anapparatus in which a servo-motor controls the gate of the turbine, orequivalent member, and is controlled or governed in turn by a pilotelement or valve ,actuated primarily by a centrifugal type governor, thegovernor operating thru a lever on a control member in the line forsupplying energy to the motor.

It has been found desirable in such apparatus to provide an inherentspeed drop"; that is, the

turbine speed is somewhat lower under higher loads and at larger gateopenings than under lower loads and at smaller gate openings. Suchinherent speed drop has come to be generally considered a necessary evilwithout which it is impracticable to obtain sensitive and stablegoverning. In order to maintain a constant speed at all loads, asupplementary mechanism, usually in the form of a synchronizing motor,is provided which acts thru suitable mechanism on the ..a) lever towhich the ball governor is connected, such motor being regulated byelectrical devices sensitive to the frequency changes of the electricgenerator which ordinarily forms the load of the turbine.

An additional difliculty which has been encountered in systems of thetype above mentioned is that in many cases there is a considerable timelag between the movement of the lever caused by the centrifugal governorand the response of the system which carries such lever back to itsnormal position. In the type of system under consideration, anappreciable time lag in the response by the turbine to the movement ofthe gate will result in an over-travel and so-called hunting of thegovernor, thereby causing a constant oscillation of the apparatus aroundthe desired position of equilibrium.

This evil is usually lessened by the addition of compensating devicesconsisting of springs'and a dash pot connected to the fulcrum of thegovernor operated lever. Such compensating dash pot mechanism reducesthe time required for the governing mechanism to reach its position ofequilibrium, but the springs used'therewith 5.; tend to give a slowadditional opening of the gate if the speed is not restored to normal.When'the time lag is a matter of a fraction of a second only, suchcompensating devices work satisfactorily, but when the time lag is ofthe order of minutes as happens in certain systems, for instance incombustion control for steam boilers, the compensating devices are notsufiicient to eliminate the hunting. Moreover, in the case of large timelag, a device providing sufiicient compensation will reduce thesensitiveness of the governor. The problem is complicated by the factalso that the correctness of the regulation is proportional to theinherent speed drop. This results that, in caseof large time lag, thespeed fluctuations due to a given change in load will be relativelylarge and that,

if the load fluctuations are quicker than the time lag, the turbine willbe hunting and out of control.

It is the principal object of my invention to '75 provide a governing orregulating apparatus adapted to minimize the above mentioneddifficulties.

The novel features of my invention are pointed out in the appendedclaims. In order, however, that my invention, together with its objectsand advantages, may be readily and fully understood,

I will now describe in detail and in connection with the accompanyingdrawings, several forms of governing or controlling apparatus inaccordance with my invention and which have been selected by way ofexample from a number of possible embodiments thereof. In the drawings,

Fig. 1 is a diagrammatic view of an apparatus in accordance with myinvention and adapted to control a turbine gate by fluid actuatedservomotors, the parts being shown in the position of equilibriumassumed at constant speed.

Fig. 1a is a detail sectional view taken on a line la1a of a pair ofmotors and associated gearing appearing in Fig. 1 and looking in thedirection of the arrows.

Fig. 2 is a fragmentary view of a portion of a system similar to thatshown in Fig. 1, but con- 10o taining compensating devices.

Fig. 3 is a view of a system similar to that shown in Fig. 1, butmodified to employ a single reciprocating servo-motor.

Fig. 3a is a detail sectional view taken on a accordance with myinvention employing an elecn trical servo-motor and designed for fuelcontrol or like purposes.

Fig. 5 is a sectional view, parts being broken away, of one of thedifferential drives appearing in Fig. 1. a

Referring more particularly to Fig. 1, is a governor of the centrifugaltype whose weights change their position in response to changes inzontal arms 45, 45.

speed of a water turbine or like prime mover 11 whose speed it isdesired to regulate. The collar 12 of governor 10 operates a pilotmember 14 shown as being formed by a rod and which is moved by governor10 in either direction from a neutral position in response to changes inspeed of the turbine. In the arrangement illustrated, the governor actson rod 14 thru a lever 16, one end of which is pivoted to a nut 18 on aworm spindle 20 which is operated thru suitable gearing by an adjustingmotor 22, whereby the neutral point of the governor 10 and member 14 maybe'adjusted as desired. Such motors are commonly known to users ofgoverning apparatus as synchronizing" motors because they are usedchiefly when synchronizing. However, spindle 20 may be hand operated ifdesired. The purpose of the spindle 20 when associated with gearing forchanging the fulcrum of the lever 16 will appear hereinbelow, but itwill be understood that such arrangements are not new in the art andthat I do not limit myself thereto. On the pilot member 14 is a primarypilot valve 28 while the lower end of the rod 14 is pivotally linked toa lever 30 having a fulcrum at 32 which is movable in the plane of lever30 in either direction from a neutral position. Pivoted to lever 30 alsois a rod 34 which carries two auxiliary pilot valves 36 and 38 whichphysically may be considered as one valve having two control grooves foractuating fluid.

The gate 39 of turbine 11, or other main member which it is desired tocontrol is shown as operatively connected to a shaft 40. For maintainingsuch gate in its desired normal position, means are provided forrotating shaft 40 in one direction or the other, depending on whetherthe speed is above or below normal. For this purpose I have illustratedtwo servo-motors 42 and 44 coupled to the shaft 40 thru suitable gearing46 which is of known type and includes a cross 41 fixed to the upper endof shaft 40 and having a pair of vertical arms 43, 43 and a pair ofhori- A pair of bevel gears 47 are swivelled on vertical arms 43 andanother such pair 49are swivelled on horizontal arms 45. Gears 47 and 49are intermeshed and gears 47 are connected by irreversible drivesincluding worm wheels 51, 51 one to motor 42 and one to motor 44 so thatwhen one motor operates, the

wheels 49 roll on the gear 47 of the stationarymotor and so turn cross41 and shaft 40. Motors 42 and 44 turn shaft 40 in opposite directions.Motors 42 and 46 are adapted to be operated by energy supplied bypressure fluid from a source 48. For purposes of convenience, the pathsof pressure fluid used for operating the main servomotors 42 and 44 areshown in relatively heavy lines to distinguish from the paths of fluidused for other purposes. The path of the fluid from source 48 to motor42 includes a conduit 50 which extends to a main cut-off valve 52. Fromvalve 52 the liquid is conducted by a pipe 54 to a branch point 56 fromwhich point fluid for motor 42 flows to a valve 58 thru a branch conduit54a.

From valve 58 fluid passes thru a conduit 60 and an auxiliaryservo-motor 62 to the motor 42.

Fluid discharged from motor 42 is returned by line 64 to a sump 66 fromwhich it is pumped back tothe reservoir 48 thru line 68.

The path of energy fluid from reservoir 48 for operating motor 44, afterpassing thru lines 50 and 54 to the point 56, as previously described,instead of passing thru branch 54a, turns at the point 56 into branch54!: and passes thru valve 70 and line '72 to auxiliary motor 74 andthence to servo-motor 44 to operate the shaft 40 in theQDPosite'direction from that in which it is turned by motor 42. Frommotor 44 the energy-conveying fluid returns to the reservoir 48 thruline 64, sump 66 and line 68. l

The auxiliary motors 62 and 74, when used, form part of a restoringmechanism whereby the valves 36 and 38 are moved back toward theirnormal position while the servo-motor mechanism is operating on shaft40. By such restoring mechanism, as will hereinafter more clearlyappear, the motion of the shaft 40 is rendered independent of the returnmotion of pilot valve 28 to its normal position thereby rendering theapparatus as a whole free from hunting and permitting it to be given anisochronous characteristic without the accompanying disadvantagespresent in previous isochronous governing mechanisms. In the arrangementillustrated for this purpose, auxiliary motors 62 and 74 are connectedthru sutable gearing 76 (shown as of the same construction as gearing46) to a threaded shaft 78 on which is a threaded nut 80, the positionof which afiects the position of the lever 30 and the rod 34 by anarrangement now to be described. As previously mentioned, one end oflever 30 is connectedto the pilot rod 14. The other end of lever 30,however, is pivoted on a lever 82 one end of which is fulcrumed at 84and the other end of which is pivotally connected thru a link 86 to thecenter of a lever 88 one end of which is pivoted on the nut 80.Therefore, whenever the servo-motor means of which motors 42 and 44 forma part is in operation, one of the motors 62 and 74 turns the rod 78thru the gearing 76 to move nut and thereby affect lever 30 and valves36 and 38. The parts are so connected also as to move the rod 84 in thedirection toward its neutral position, whichever one of auxiliary motors62 and 74 happens to be in operation.

Preferably, the other end of lever 88 is pivotally connected to the rod90 of a piston 92, the motion of which also necessarily has a restoringeffect on lever 30 and pilot member 34 and the valves associatedtherewith because of the connection between lever 88 and lever 30. Theoperating fluid for piston 92 is controlled by the valve 36. The pathfor such fluid is shown in light lines and the same plan is followed forshowing the paths of fluid for all auxiliary purposes. The path of fluidfor piston 92 branches from the line 50 at the point 94 and flows thruthe line 96 to the valve 36. Valve 36 controls two ports which areconnected to opposite ends of the cylinder for piston 92 thru lines 98and 100. When the valve rod 34 and valve 36 move in one direction 92 andthe other involving differential gearing '16, produces in general thesame eflect on the lever 30 and the auxiliary pilot valve 88, the use ofthe piston operated restoring means alone is not so desirable as the useof the two restoring means for the reason that the piston restoringmeans must be either geared up or have a very long piston travel it itis to act alone, thereby reducing its sensitiveness. Similarly, the useof a geared restoring means alone produces a control or regulatingmechanism of insuflicient sensitiveness and one containing possibilitiesof stalling under certain conditions. However, I do not limit myself tothe use of either of the particular restoring means above described. Inthe arrangements shown, such restoring motion renders the movement ofshaft 40 substantially independent of the return movement of the mainpilot member 14, an important feature of my invention. It is obtained inthe following way:

The flow or energy to the main servo-motor means is controlled byrelays, the motive fluid, or energy, for which is controlled by the position of valves 28 and 38. In the arrangement shown, the main pilotvalve 28 receives energycarrying fluid from the line 96 and controls twoports one or which connects to a line 102, the other of which connectsto a line 104. Line 102 runs to the cylinder of a relay piston 106.Fluid discharged from cylinder of piston 106 passes thru line 108 toline 110 and thence to the sump 66. Fluid passing thru the line 104flows to the cylinder of a relay piston 112. Fluid discharged from thecylinder of piston 112 flows thru line 114 to the line 110 and thence tosump 66. The outlets 10"! and 113 for fluid from the cylinders forpistons 106 and 112 are restricted so that pressure builds up quickly inthe cylinders to operate the pistons whenever valve 28 opens the properports. Pistons 106 and 112 are both single-acting and serve to throwvalves 58 and 70 respectively into position to permit energycarryingfluid to flow thru the lines controlled thereby. Pistons 106 and 112being single-acting, valves 58 and 70 are returned to normal position inwhich flow through such valves is cut off by means of springs 116, 116.When either valve 58 or valve 70 is in open position, energy can notflow to the servo-motor means unless the valve 52 is also open. Thevalve 52 is operated by a piston 118, the operating fluid for which iscontrolled thru two auxiliary valves 120, 120 one of which is on thestem of valve 58 and the other of which is on the stem of valve 70.Fluid for operating piston 118 is also controlled by pilot valve 38 inseries with the valves 120. When pilot valve 28 is moved by the governor10 in a given direction so as to operate one of the valves 58 or'lO, thevalve 38 is also operated in the same direction and so that fluid.

passes into one of the lines 122, 122 from one oi! its ports. from theline 96 and passes from. valve 38 into one of lines 122 which lead thruthe valves 120 into a. common line 123 which supplies the cylinder ofpiston 118.- Piston 118 also is of the single-acting type and isreturned to its normal or inoperative. position in which flow throughsuch valves is cut off by a spring 116. Its cylinder also has arestricted discharge, permitting the omission of further control means.Fluid discharged from the cylinder of piston 118 flows thru line 124 toa line 110. It will appear, therefore, that the movement of the pilotvalves 28 and 38 in a given direction will open a path for Fluid forthis purpose is derived the energy fluid to pass to the servo-motors 42and 44 to operate the shaft 40 in the appropriate direction. It will benoted, however, that the valve 38 has an overlap 39, 39 on both itsoutlet ports, the purpose of which is to prevent the motion or the mainservo-motor means from being aiiected by the return motion of main pilot28 toward normal position after it has initiated a movement of the mainservo-motors.

It will be understood that the description of function and results givenherein, in so far as speed regulation is concerned, applies only tocases in which the changes of speed are caused by changes in load, as itis considered impossible that a governing mechanism off-set the effectsof changes in pressure of the medium driving the prime mover.

While the operation of the mechanism above described will be obvious tothose skilled in the art from the foregoing description, it may be1summarized for purposes of convenience as folows:

Roughly speaking, the operation of the governing or regulating apparatusis divided into three periods.

First peri0d.Assuming an increase of load with consequent decrease inspeed of the turbine 11, the movements are; rod 14 and with it mainpilot 28 and auxiliary pilots 36 and 38 move downwardly. Thru the lowerleft hand port of the main pilot 28 fluid passes thru line 104 to piston112 of valve causing valve 70 to open. Thru the right hand lower port ofvalve 36 the fluid begins to fill the space below the piston 92 of therestoring mechanism, thereby moving such piston upwardly and also movingup thru links 88, 86 and 82 one end of the lever 30 and therebysimultaneously moving upwardly the auxiliary pilots 36 and 38 towardclosed or neutral position to thereby cut off fluid flow therethrough.Thru the lowerright hand port of auxiliary pilot valve 38, fluid passesthru one of the valves 120 which was opened by the movement of mainvalve 70, into the cylinder of piston 118 thereby opening the main powervalve 52. Valve 52 and one of the valves 58 or 70 thus being open, theservo-motor apparatus is operated. Since valve '70 is assumed to beopened, the motor 44 will operate and such operation continues to theextent of operating the shaft 40, and thereby the turbine gate, to anextent proportional to the initial displacement of pilot valve 28.

The turbine gate is moved proportionately to the change in speed becausethe change of speed is assumed to be due to a change in load. Hence, aproportionately greater gate opening is required to carry the new loadat the original speed. The mechanism illustrated in Fig. 1 causes suchproportional movement of the gate for the reason that the mainservomotors 42 and 44' run throughout the time during which theauxiliary pilots 36 and 38 are returning to their new positions afterhaving been displaced by the movement of the main pilot control valve28. But the mechanism which restores members 36 and 38 to neutral is,throughout such period, being operated by motor 62 or 74, both of whichare propelled by fluid at constant pressure derived from reservoir 48and move therefore at a constant rate of speed because the load on suchmotors is obviously constant. The length of time required for members 36and 38 to return to the neutral position is therefore proportional totheir initial displacement away from neutral caused by movement ofmember 28. However, motor 42 or motor 44 runs until members-86 and 38reach their neutral positions. Motors 42 and 44 also are constant speedmotors, operating under constant pressure from reservoir 48 and runthroughout the periods the auxiliary pilots 38 and 38 are returning totheir neutral positions. The movements of the gate produced by 42 and 44are therefore also proportional to the initial displacement of the mainpilot valve 28, movements of members 36 and 38 away from their neutralobviously being proportional to the movements of member 28 away from itsneutral. However, the restoring mechanism moves the valves 36 and 38back to neutral thereby cutting off the restoring action of piston 92and also cutting off the flow of energy to the piston 118 of main stopvalve 52. The condition at this point, which is assumed to be the end ofthe first period, is such that the turbine speed is increasing but notyet normal due to the time lag, so that the pilot valve 28 is not inneutral position. Consequently, the valve 70 remains open but there isno flow of energy to the servo-motor means because the stop valve 52 isshut.

Second period-The second period starts when the turbine begins to speedup, thus overlapping somewhat the first period. During the secondperiod, the pilot valve 28 begins to move toward its neutral due to thegoverning action, but valves 36 and 38 having been already moved toneutral position by the restoring means are then moved into positionabove neutral, thus supplying actuating fluid to the space above piston92 and such piston thereupon begins to return the pilot valves 36 and 38to neutral. The main stop valve .52, however, remains shut because ofthe overlap 39 of valve 38 which covers the lower port of such valve andthe opened upper port can not pass fluid because the circuit for thepiston 118 is closed by the auxiliary valve 120 belonging to the closedvalve 58 and valve 58 is maintained closed by the position of pilot 28which is below the neutral. Therefore, during the second period, theturbine gradually speeds up, shaft 40 remaining stationary so that thegate remains in the position given it during the first period. Therestoring piston 92 slightly over-balances the movement of the mainpilot 28 in its effect on lever 30 to bring the pilots 36 and 38 intoneutral. Such restoration of valves 36 and 38 to neutral is important inthat it restores the sensitiv-eness of the governing system so that itcan respond to a further slowing down of the turbine if an additionalincrease in load occurs during the second period.

Third period.-The third period occurs only occasionally and is producedin cases where the time lag is considerable and the increase in loadwith consequent decrease in speed is continuous. Under suchconditions,the amount of opening of the gate effected during the first period isinsufiicient and consequently the governor 10 will not bebrought back tonormal speed and the pilot valve 28 will not reach its neutral position.The governing system, however, will be inactive because the pilot valves36 and 38 have been restored to their neutral positions.

There is thus a residual error in the operation of the system asheretofore described for conditions stated under the third period, and Iprefer to provide means for correcting such error. In the arrangementshown for this purpose the fulcrum 84 of lever 82 has the form of a camsurface which rests upon a rotating cam member 126. The cam member 126causes a continuous oscillation of lever 82 which is communicated thrupivot 32 and lever 30 to the auxiliary pilots 36 and 38 as areciprocating action. Pilot 28 being below its neutral, no effect isproduced by cam 126 when it lifts pilots 36 and 38 above their neutrals,but when the cam permits valves 38 and 38 to drop below their neutralsthere will be a slight additional movement of servo-motor 44 and shaft40 in the same direction as assumed in theflrst period. If the speed iscorrect the action of cam 126 will not produce any movement of shaft 40because pilot 28 is shut.

In the arrangement illustrated in Fig. 1, separate motors 62 and 74 areprovided as part of the restoring means. Such servo-motors 82 and '74are, however, the equivalent of driving the spindle 78 by gearing fromthe spindle 40, motors 62 and 74 each operating concurrently with one ofthe motors 42 and 44.

The system illustrated in Fig. 1 does not contain any meanscorresponding to the damping device usually employed in governormechanisms. Whenever conditions make it advisable to employ such dampingmeans in connection with my invention, it may be provided convenientlyby interposing such clamping device between the levers 82 and 88. Suchan arrangement is illustrated in Fig. 2 in which the link 86 forsupporting the lever 82a is connected to a lever 87 one end of which isconnected to a dash pot 128 and the other end of which is connected to apiston 13 whose normal position is determined by springs 132 and 133acting on its opposite face. Lever 87 is connected at its center by link134 to the lever 88a. Otherwise, the arrangement of Fig. 2 is assumed tobe the same as that illustrated in Fig. 1, parts havingthe same functionin the two arrangements having the same reference character.

While the apparatus within my invention can notv altogether preventvariations in speed of turbines used to drive generators due todisturbances on the lines, which cause the generator whose turbine maybe governed by my apparatus sometimes to become motorized, as it iscalled in the art, even in such cases, the apparatus in accordance withmy invention is adapted to maintain the turbine load fluctuations withinmore narrow limits than do the governors in accordance with the priorart.

In case rotating motors such as 42 and 44 are too slow for theconditions under which the tur bine is to operate, the arrangement suchas that illustrated in Fig. 3 may be substituted and in which a piston134 and its associated cylinder 135 is used instead of motors 42 and 44.In such an arrangement, valves 58 and 70 are substituted by two-wayvalves 58a and 70a, the arrangement otherwise being the same asindicated by the reference character on Fig. 3, except as to the conduitarrangement for the energy conveying liquid between valves 58a and 70aand the sump 66. As shown in Fig. 3 conduit 65 extends from the upperhigh pressure port of valve 58a to a junction point 61 from which pointthe operating liquid is conveyed by conduit 60!; thru reversible seriesmotor 62A to one end of the cylinder of piston 134 to move such pistonin one direction, which will be called the forward direction. On thereturn stroke of piston 134, however, liquid flows from the cylinderthru motor 62A and conduit 60a to point 61 and thence thru conduit 63 tothe low pressure or return port of valve 70a thru which it flows topoint 65 where it enters return conduit 64. The power fluid for thereturn stroke of piston. 134 is delivered by valve a to conduit 72 thruwhichit flows to iunction point '13 and thence it flows by, conduit'lzathru reversible series motor 74A to 'the other'end of the cylinder ofpiston 134 to operate such piston on its return stroke in the oppositedirection to that in which it is moved by fluid reaching its cylinderthru conduit 60a.

When new the piston 134 has completed a given retumstroke andjthepositions of valves 58a and 70a have been shifted so as to cause asecond forward stroke, liquid flows fromcylinder 135 thru pipe orconduit'72a'to branch point73 and thence thru conduit '15- to the lowerport of valve 580 and thru such valve tothe common-retum conduit 64 atjunction point 65. It will benoted from Figs. 1a and 3a thatthe motors62A and 74A- associated with the gearing '76 in Fig.3 are of'the sametype as the motors 62 and '74 associated with the gearing 76 of Fig. 1.The motors 62 and 74 of Fig. 1 need turn in one direction only, theliquid flow through such motors being in one direction only. The motors62A and 74A, however, must reverse in order to permit the operatingliquid to flow into and out of the opposite ends of the reciprocatingpiston motor 135. In order therefore, that the motors 62A and 74A shallhave the necessary action on the adjusting rods 78 and nuts 80, theoperating shaft of motor 62A is connected tothe right hand gear of suchmotor and the operating shaft of motor 74A is connected to the left handgear. This distinction between motor 62A and motor 74A is indicated inFigs. 1a and by crosses (x) on the axes of the gears having themotorshafts fixed thereto. It results that, when the fluid is passingthru motors 62A and 74A in opposite directions, the driving shaftsacting on the gearing '16 turn in the same direction. The differentialfeature of gearing 76 therefore is not so important in Fig. 3 as in Fig.1 although it is I preferred to use a differential gear in Fig. 3 inorder to accommodate any slight diiferences of speed between the motors62A and 74A and/or back-lash of liquid in motorl35.

in some cases of remote control, it is desirable to utilize electricenergy in place of the liquid assumed in the arrangements illustrated inFigs. 1, 2 and 3. Such an electric system is illustrated in Fig. In Fig.4, it is assumed that the mechanism is to be utilized for combustion orpressure control instead of for speed control so that a diaphragm 13?within a casing 136 supplies the initial impulse for moving the pilotmembers from their neutral positions. As illustrated, pressuredifferences are set up on each side of the diaphragm within casing 136by fluid entering such casFng thru pipes 138 and 140 on opposite sidesof the diaphragm, pipe 138 being connected, for instance, to a source ofvariable pressure such as boilerand pipe 140 connected to a source ofconstant pressure produced by any suitable or known means. The diaphragmis connected to a rod 142 the-movements: of which. are transmitted tothe lever 16 which connects'in turn with the pilot rod 14. Surroundingrod 142 is a spring 142A which serves to fix approximately thezero orneutral point of the diaphragm. The neutral point of the-pilot member 14and the pilot contact 2813 may, however, l e-adjusted during operationwhen desired, for given spring-142A and constant pressure sourceattached to pipe 140, by adjusting one end of lever 16 by operatingadjusting motor 22; On the pilot rod 14 is-fixed a movablecontact 281)which is connected thru line 961) with one sideof an auxiliary circuit97 for supplying the electricenergy' to the contacts and relays of whichare shown in heavy lines.

thru line 1021) with an operating relay 106!) the other side of whichconnects to the circuit 97 thru line 10817. The lower of the contacts96' connects thru the line 104b with the relay 112b, the other side ofwhich connects to the circuit 9'! by line 1141). Relays 106D and 11222control the switches 58b and 70b of a reversible servo-motor 134?; foroperating the shaft 40. If the apparatus of Fig. 4 is to be used tocontrol the pressure in a steam boiler having dampers and/or fuel valves(not shown), the shaft 40 of servo-motor 1441) is connected to open suchdampers and fuel valves whenever the shaft turns in one direction and toclose such dampers and fuel valves when the shaft 40 turns in the otherdirection. In the illustration of the arrangement of which motor 134?)forms a part, I have shown also arranged in series with whichever one ofthe switches 58b or b is in closed position a main switch 52b having arelay 11% the current for which is supplied from the circuit 9'? thrulead 96b, movable contact 38b on rod 34b and one of the fixed contacts38', 38'.

From either of the fixed contacts 38' current flows to the relay 118bthru one of the leads 1222). Each of leads 12212 has in it a switch1201) which is fixed to the rod of one of the switches 58b or 70b sothat one of switches 12012 is closed whenevereither of switches 58b or70b is closed. Line 12212 joins after passing thru switches 12Gb in lead123D which conducts the current to the relay 118D from which it returnsto the circuit 9'7 thru line 124b.

Rod 34b has thereon also a second movable contact36b which is adapted tocontact with either of fixed contacts 36', 36' depending on thedirection and motion of rod 34b from its neutral position. Rod 34b ispivoted to a lever 30 which is pivoted in turn at point 32 to a lever82. One end of lever 62 is supported at 84 on a rotating cam 126 whilethe other end of lever 82 is pivotally supported by alink 86, the upperend of which is pivoted to the centre of lever 38. One end of lever 68is pivoted to a nut and the other end of lever 88 is pivoted to a nut b.Parts 30, 82, 86 and 88 of the arrangement illustrated in Fig. 4 havethe same functions as'the same parts in the apparatus of Fig. 3. Thelever 68 therefore forms part of a restoring means for restoring the rod34b and its associated contacts to a neutral position irrespective ofthe motion of the pilot rod 14. To perform this function, nut 80 whichsupports one end of the lever 88 is threaded on a shaft 78b which isturned in one direction or the other by a motor 62b connected inparallel with the motor 134b. The nut 90b which supports the other endof lever 88 is threaded on a shaft 90 which is operated in one directionor the other by a motor 92b the circuit for which is controlled by twoswitches 150, 150, the relays 152, 152 for which receive operatingcurrent from the contact 36b and either one or the other of contacts36'. Each of contacts 36' connects with one of the relays 152 thru oneof the lines 154, 154. The other side of relays 152 connects with therelay operating circuit thru the return leads 156. 156. Switches 150 areconnected in parallel with the power line 50b for the main servo-motor134b and the line 156 for the restoring motor 92b. It will be seentherefore that in the arrangement illustrated' in Fig. 4 the restoringmotion is given the rod 34b both by the motor 62b which operates at thesame time as the main servo-motor 13412 and also by the motor 92b whoseaction is controlled by' the position of rod 34b itself. It will be seenthere.- fore that the action of the apparatus illustrated. in Fig. 4 isquite similar to that illustrated in Figs. 1 and 3 so that it need notbe further described.

In each ofthe mechanisms shown in Figs. 1, 3, and 4, I have illustratedmeans foreign to the regulating system for effecting corrections ofperformance, and shown as a synchronizing mechanism comprising parts 18,20 and- 22 and connected to the lever 16. Such synchronizing means iscommon in the art and I do not limit myself thereto, altho its use isadvantageous in making final adjustments to compensate for inaccuraciesin the action of the governor or controlling mechanism due to anyinaccuracies of construction or adjustment as well as to damp thedepartures from normal speed which will be inevitably caused by linedisturbances, some of which produce conditions which it is impossiblefor any governing mechanism to completely counteract.

While I have described the structures illustrated in Figs. 1, 2 and 3 asarranged to control the speed of a turbine or like prime mover and havedescribed the structure ilustrated in Fig. 4 as arranged to control thepressure of a boiler or the combustion in a furnace, it will be evidentthat the structures of Figs. 1, 2 or 3 may be utilized for controllingpressures, rates of combustion, or other functions, while the apparatusillustrated in Fig. 4 is adapted to control the speed of a prime mover,equally well as the structures of Figs. 1, 2 and 3, the rod 142,however, being substituted in such case by the collar of a ball governoras in Fig. 1. In general, the electric embodiment of the inventionillustrated in Fig. 4 is less expensive than the hydraulic apparatusesof Figs. 1 and 3, but cannot be employed where there is danger ofexplosion.

A comparison of the foregoing embodiments of my invention with apparatusaccording to the prior art shows that while, in usual governors orregulators, the gate, or the like regulated element, follows the forwardand return motion of the ball governors rod and different gate openingsare secured by allowing a so-called inherent speed drop, in apparatus inaccordance with my invention, the gate, or the like, does not follow thereturn motion of the regulating rod, being pre-' vented from so doing bya combination of valves or members, controlled by an auxiliary pilotvalve, or member. This allows apparatus in accordance with my inventionto operate without the inherent speed drop while having at the same timea damping effect produced by the restoring motion. The so-calledisochronous governors may also operate without an inherent speed drop,but they are unstable because of the lack of restoring motion which inturn allows continuous hunting between the xtreme gate positionswhenever there is the htest time lag. A governor or regulator mechanismin accordance with my invention is inherently isochronous, while thevarious gate openings are secured by the action of mechanism which stopsthe gate movement during the return of the ball governor's rod toneutral position. For other purposes than turbin'e speed regulation,apparatus in accordance with my invention achieves a correctcorrespondence between the movement of the regulatedv element combustioncontrol apparatus for steam boilers,

for keeping steam pressure or steam temperature .constant at varioussteaming rates, and for regulating other features of steam generation.

In short, in apparatus in accordance with my invention the position ofthe regulated element is always proportional to the algebraical sum ofthe displacements'of the governors collar, or other regulating element,away from its neutral or normal position.

What I claim is:

1. In a governor or regulating apparatus the combination with a pilotelement adapted to move in either of two directions from a neutralposition in response to changes in a condition which it is desired tomaintain constant, means for moving said element in response to thechanges in said condition, a second pilot member auxiliary to saidelement and also moved by said means, a motor driven means adapted tooperate in either of two directions for altering said condition, andmeans whereby said first pilot element and said auxiliary pilot membercontrol said motor driven means, said control means comprising a pair ofenergy controllingmembers in the path of the energy supply of the motorof said motor driven means, one member of said pair controlling a givendirection of movement of said motor and the other controlling theopposite direction of movement of said motor driven means, means wherebysaid pair of members are controlled by the position of said first pilotelement, another energy controlling member in the path of the energysupply of said motor and arranged to act in series with whichever one ofsaid pair of members is active, and means whereby said last mentionedmember is controlled by the position of said auxiliary pilot member.

1 2. In a governor or regulating apparatus the 1 3. In amotor-operated'governor or regulating apparatus, the combination of apilot element arranged to move in either direction from a neutralposition, a lever having a pivot and operated by said elemen anauxiliary pilot member operated from said lever, a maingoverningelement, and motor means'for moving said main element in one directionor the other as circumstances may require andincluding two energycontrolling members arranged to act in series on the energy supplied tothe motor of said motor means,-means whereby one of said energycontrolling members is controlled by said first pilot element and theother by said auxiliary pilot member, and means for moving saidauxiliary pilot member in the direction toward its neutral a poweroperated means for effecting changes 5;, v

to counteractsaid variations, a system of members for controlling flowof actuating energy to said power means and so associated with saidelement that,'when the variation of condition indicated by said elementhas been corrected, said power operated means stands still while thefull response of the regulated system to the new setting of parts bringssaid elements back into neutral position whenever there is no additionaldeparture from the desired condition of the regulated apparatus duringthe return movement of said element, a mounting for said pilot elementadapted to'bring it to rest when normal periormance oi the regulatedsystem is reached, and including an auxiliary element mounted to moveaway from its neutral position whenever said pilot element is displacedfrom neutral and means for restoring said auxiliary element to neutralwhile said pilot element is still displaced therefrom, said meansadapted to fix the relation between the final amount and direction ofthe displacements of the power means and the initial amount anddirection of the corresponding displacements of said pilot element awayfrom the latters neutral position.

5. The combination in a regulating mechanism for keeping constant acertain condition of the pilot elements responsive to the variation fromthe desired condition, power operated means for effecting changes tocounteract said variations, a system of members having control of theflow of actuating energy to said power actuated means and so associatedwith said pilot element that, when the variation of condition indicatedby said pilot element has been corrected, said power operated meansstands still while the full response of the regulated apparatus to thenew setting of parts brings said pilot element back into neutralposition whenever there is no additional departure from the desiredcondition of the regulated apparatus during the return movement of thepilot element, said system of members for controlliing the actuatingenergy including a first control member direct connected to said pilotelement, a floating lever one end of which is connected to the firstelement and a restoring mechanism to which the other end of said leveris connected, two other control members connected to move together andto be operated by an intermediate point or part of said lever, meanswhereby the one of said control members connected to said lever afiectssaid restoring mechanism, and means whereby the other of said controlmembers connected to said lever indirectly controls the flow of energyto said power operated means.

6. The combination in a regulating mechanism for keeping constant acertain condition in a regulated apparatus of a pilot element responsiveto the variation from the desired condition in said apparatus, a poweroperated means for efiecting changes in the regulated apparatus tocounteract said variations, a system of members for controlling flow ofactuating energy to said power means and so associated with said pilotelement that, when thevariation of condition indicated by said pilotelement has been corrected, said power operated means stands still whilethe full response of the regulated apparatus to the new setting of partsbrings said pilot element back into neutral position whenever there isno additional departure from the desired condition of the regulatedapparatus during the return movement of the pilot element, said systemof members including a first control member direct connected to saidpilot element, a floating lever, one

end of which is connected to said pilot element, a restoring mechanismto which the other end of said lever is connected, two control membersconnected to move together and to be operated by an intermediate part ofsaid lever, means whereby one or said two control members connected tosaid leveraflects said restoring mechanism, and means whereby the otherof said two control members connected to said lever controls the flow ofenergy to the power operated means. said last mentioned means includinga pair of power control members one in the line 01 the power element forforward running and one in the line of the power element for reverserunning and a third power control member in series with both said powercontrol members, means whereby the control member on said pilot elementcontrols said pair of power control members, a pair of additionalmembers connected to operate simultaneously with said pair of powercontrol members and adapted to inhibit or permit the operation of saidseries power control member, and connected between the said members soconstructed and arranged that when the second and third control membersconnected to said lever are brought to neutral by said restoring motionand then carried beyond neutral by thereturn motion of said pilotelement toward its neutral, the energy for the power element is cut oil.

7. A governing or regulating mechanism having substantially zeroinherent speed drop and comprising a pilot element, a regulatingelement, a servo-motor for moving said regulating element in onedirection or the other depending upon the position of said pilotelement, a lever directly connected to said pilot element, a movablefulcrum ior one end of said lever, an auxiliary pilot member connectedto an intermediate point of said lever, means controlled by thedisplacement of said pilot members in a given direction from theirneutral positions for operating said servo-motor in one direction or theother, 7

9. The mechanism as set forth in claim 7 together with a continuouslyrotating member arranged to produce an oscillation of the lever to whichthe auxiliary pilot member is connected.

it). The combination in a governing mechanism of main and auxiliarypilot members, means for moving said main member in either directionfrom a given position in response to changes in a condition which it isdesired to maintain as con stant as possible, means whereby saidauxiliary pilot member is moved one way or the other from a neutralposition at the same time said main pilot member is moved away from itssaid position, a servo-motor, means for conducting energy to said motor,means whereby initiation of the flow of energy to said motor throughsaid means is controlled by said main pilot member, means for restoringsaid auxiliary pilot member to its neutral position ahead of the returnof the said main pilot member to its original position, and

position. Y

11. The combination as set forth in claim 10 and in which the means forrestoring the auxiliary pilot member is adapted and arranged to restoresuch auxiliary member substantially to its neutral position prior to thebeginning of the return movement of the main pilot member toward itsgiven position.

12. The combination as set forth in claim 10 and in which the parts areso arranged that the movement of the auxiliary pilot member toward itsneutral position has substantially no effect in assisting the movementof the main pilot mem-- her to its given position.

13. The combination in a governing mechanism of the servo-motor type ofa main pilot member and an auxiliary pilot member both having neutralpositions, a servo-motor, means including said main pilot member, forsupplying energy to said motor, and means for interrupting the action ofsaid means when said auxiliary pilot member is in its neutral positionirrespective of the position of said main pilot member;

14. The combination in a governing or regulating mechanism of theservo-motor type, of a servo-motor means, a source of supply of energytherefor, means for conducting energy from said source to said motormeans including a line leading from said source and having two branchesextending from a branch point to said motor means, a means individual toeach of said branches for controlling the passage of energytherethrough, a means individual to the portion of said lineintermediate said source and said branch point for controlling the flowof energy through such portion, a main pilot element, means whereby themotion of said pilot element causes the energy controlling means in oneor the other of said branches, depending on the direction of saidmotion, to assume a position to pass energy to said servo-motor means,an auxiliary pilot member, means whereby said auxiliary pilot membermoves at the same time as said main pilot element whenever the mainpilot initiates a movement which is to cause the energy controllingmeans in one of said branches to assume a position to pass energy,energy using means whereby said auxiliary pilot member causes the energycontrolling means in said portion of said line between said source andsaid branch point to pass energy whenever such auxiliary pilot movestogether with said main pilot and irrespective of the direction ofmotion of the auxiliary pilot, and means individual to each of theenergy controlling means in said branches and adapted to interrupt theaction of said energy using means to permit the interruption of flow ofenergy to said servo-motor means.

15. The combination in a regulating mechanism of a main pilot member andan auxiliary pilot member connected together, a servo-motor means, meanswhereby simultaneous motion of said pilot members in directions awayfrom given positions inaugurates flow of energyto said servomotor means,and means for restoring said auxiliary pilot member to its givenposition ahead of said main pilot, said restoring means including meanswhereby the auxiliary pilot is moved toward its own given position tocompensate for the return movement of the main pilot member toward itsown given position, said energy inauof energy to said servo-motor means.

gurating means including means whereby an overrunning of said auxiliarypilot on its return movement due to the return motion of said main pilotmember is ineffective to inaugurate a flow 16. The combination in agoverning or regulating apparatus for keeping constant a certaincondition in a system controlled thereby and having an arrangementproducing a substantially zero inherent speed drop of a pilot elementhaving'a neutral position, a servo-motor means, and mechanism includingparts for controlling the fiow of energy to said servo-motor meanswhereby such means is caused to operate in one direction or the otherdepending on the displacement of said pilot element from its neutralposition, said mechanism adapted to remain unaffected by movements ofsaid element in the direction toward its neutral position irrespectiveof the speed of response of the said controlled system.

1'7. The combination in an apparatus as set forth in claim 16 and inwhich the parts are constructed and arranged so that the net regulatingaction is proportional to the algebraic sum of the movements of thepilot element away from its neutral position.

18. The combination in an apparatus for governing or regulating a givencondition in a system controlled thereby and adapted to actsubstantially without inherent speed drop of a pilot element having aneutral position and adapted to move either way therefrom, and meansincluding a servo-motor and an energy supply therefor whereby the netgoverning or regulating action is proportional to the algebraic sum ofdisplacements of said pilot member away from its said neutral positionindependently of the speed of response of said controlled system, saidmeans including parts for isolating said servo motor from its energysupply during movements of said pilot member toward its neutral.

19. A regulating apparatus for keeping substantially constant a desiredcondition in a system controlled thereby, said apparatus having a pilotelement responsive to the variations from said desired condition andhaving a neutral position, a power operated means for effecting changesto counteract said variations, members for controlling the flow ofactuating energy to said power means and so associated with said pilotelement that, when the variation of conditions indicated by said pilotelement has been corrected said power operated-means stands still whilethe full response of the regulated system to the new position bringssaid pilot element back into its neutral position whenever there is noadditional departure from the desired condition of the regulated systemduring the return movement of the pilot element and independently of thespeed of response of the regulated system.

20. A regulating apparatus as set forth in claim 19 and in which themembers for controlling flow of actuating energy to the power operatedmeans are arranged to remain inoperative when the pilot element returnsto its neutral position.

NICHOLAS ARTSAY.

CERTIFICATE OF CORRECTION.

Patent No. 1,977,980. d October 23, 1934.

NICHOLAS ARTSAY.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 7,line 97-98. claim 6, for "connected" read connections; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of t the case in the Patent Office.

Signed and sealed this 8th day of January, A. D. 1935.

Leslie Frazer (Seai) Acting Commissioner of Patents.

